No effective treatment has been established yet for incurable and radioactive iodine-refractory differentiated thyroid carcinoma (RAI-refractory DTC). With the recent progress in the field of molecular biology, some gene mutations leading to thyroid carcinomas have been identified, and molecular-targeted drugs targeting these gene mutations have been developed for clinical application. Sorafenib has been demonstrated in a phase III trial to significantly prolong the progression-free survival in patients with RAI-refractory DTC. At our center, we have started to use sorafenib for RAI-refractory DTC, and herein, we report the course of treatment in these cases.
In all, 4 patients with RAI-refractory DTC have been treated with sorafenib at our department. The duration of sorafenib treatment ranged from 10 to 410 days. The side effects observed included hand-foot syndrome in 4 patients and alopecia in 3 patients. Diarrhea, hypertension, and liver dysfunction were observed in one patient. Serious liver dysfunction was observed in one patient. All patients required sorafenib dose reduction, and suspension of sorafenib administration was necessitated in two patients. Sorafenib treatment needed to be discontinued altogether in one patient because of the development of hand-foot syndrome.
We performed imaging examination at 6 months after the start of treatment, and evaluated the therapeutic effect according to RECIST. In the patient who received only short-term administration (10 days) due to the development of hand-foot syndrome, the tumor size had slightly increased (18% increase). However, in the patients who had received the treatment for several months, the therapeutic response was relatively good (0 to 25% decrease in tumor size). Hand-foot syndrome is the most commonly encountered adverse effect of sorafenib, that frequently necessitates treatment discontinuation. However, in most cases, the syndrome can be controlled by taking appropriate measures. To achieve a sufficient therapeutic effect, it is important to continue administration of sorafenib while taking measures to control hand-foot syndrome.
